Performance analysis of DWT based OFDM over fading environments for mobile WiMax

Orthogonal frequency division multiplexing (OFDM) is a powerful technology to increase the data rate transmission over mobile wireless channels. The problem with conventional OFDM in which fast fourier transform (FFT) was used to transform and map data onto orthogonal subcarriers is that it was inherently inflexible and had high complexity. Wavelet analysis offers strong advantages over Fourier analysis, as it has a time-frequency domain operation, thus allowing optimal flexibility with less complexity. This paper provides the analysis of the performance of discrete Wavelet transform (DWT) based OFDM as an alternative to the conventional FFT based OFDM systems under the joint effect of path loss, multipath fading and noisy environment for mobile WiMax in terms of bit error rate (BER). The performance measurements and analysis was done in simulation developed in MATLAB. It was observed from the simulation results that DWT-OFDM offers to lower BER and enhance the performance in mobile multipath environments for various modulation schemes.